Matt's Puzzle Corner: matts_puzz. A new puzzle every day; usually Sudoku (variable difficulty level), sometimes other similar kinds of puzzles. I also have feeds of pure Sudoku puzzles with consistent difficulty levels, but they're not syndicated to Livejournal at the moment. If you want one and can't syndicate it yourself, let me know and I'll add it.
This is mostly a publicity stunt for my Web comic, which is also syndicated as bonobo_conspir.